I think I'll give a "Gaji" perspective on this… from an OOC and IC view.
Kerby, as much as I know you want to keep everything special to the camp, and have complete unrestricted control over everything done with "Camp Boons" that you created, I find ICly there's a bit of plot holes, and marketing holes also...
When Gaji buy the items, no one is losing profit except fellow Gali who might have sold it for extravegent prices, but if other Gali saw this, they would sell it for a lower price and undercut fellow gali, and it would continue to go lower to a point that the rate charges is barely noticible anyway.
The way I'm personally interpreting your words... Discount is not "at cost". And knowing a basic idea of Gali principle, they wouldn't sell "at cost" in the first place, unless they got back the money somehow.
Now, if there was a "community pot" (suggested above), which would give Gali a "moral incentive" (as a lot of them I know are lazy when it comes to merchanting), possibly even required to upkeep the high discounts, that covers the incentive for the merchants to give the discount in the first place, and allows you to logically demonize anyone buying the items for thier gaji friends, because then they -are- actually taking away frmo the community.
Mirkali, ICly, has never been approached by Gali with a sales offer. He went in once with a host, buying some Elvish rope for himself and one bundle for his Gali host for the hospitality. Of course, he prolly wouldn't buy it for more than 90 gold anyway, he bought it only for that price because of his... eh... "hobbies" Coughs
So, personally, I think, ya, you -could- pretend that it goes to the camp, but that would still be bogus. The camp gives so many great things, that it -should- charge a tax. It's sort of a semi-guild, afterall, and a lot of guilds ((That aren't employed by cities)) have thier members have required mandated taxes or fees from time to time.
From having such a tax, this would essentially make Gali more compelled to follow the rules you laid out, and would -make sense- for most of the things (at least for me). Apart from that, it gives a standing of what Gali are loyal in the ways of donating coin to the camp -above- thier required level. And having this requirement could lead to some very interesting quests and RP.
But again, this is from the perspective of a Gaji, a bard of all things, what do they know, afterall? heh.